at the white house, spokesman jay carney says that president obama has been briefed twice on the suspicious letters and offered this update a short time ago. >> the fbi has the lead for determining whether a suspicious powder is a dangerous substance such as ricin and those take place at accredited facilities and take a certain amount of time as the fbi has indicated. you know, these procedures are in place and they're in effect and in operation now and we're in the midst of that process that the fbi is undertaking at this time. >> there's also today security activity here on capitol hill. officials not taking any chances in light of recent activity, both here and also in boston, and a suspicious package was delivered to the office of alabama republican senator richard shelby who was checked out by authorities and told we were given an all clear a short time ago. the bomb squad was sent to the nearby heart center office building. a loud speaker told senators and staffers, there was a suspicious package on the floor of the building and please avoid until further notice. that situation has be